Full Paper ACEEE Int. J. on Electrical and Power Engineering , Vol. 4, No. 3, November 2013
Safety Evaluation of Live Line operators of 1200 KV UHV AC Exposed to Electric and Magnetic Fields Mahadev Unde1 , Rohidas Maske2 and Bansidhar Kushare3
1 P. D. V. V. P. College of Engineering, Ahmednagar, India Email: mg_unde@rediffmail.com 2 Maharashtra State Electricity Transmission Company, Aurangabad, India Email: rohidasmaske2@gmail.com 3 K. K. Wagh Institute of Engineering Education and Research, Nashik, India Email: bekushare@rediffmail.com Abstract— This paper presents the study of assessment of external electric and magnetic field exposure to live line operator of 1200 KV, Ultra High Voltage (UHV) AC proposed line in India. Single circuit (S/C) and double circuit (D/C) power lines are considered for the assessment. Combination of charge simulation and image method is adopted for evaluation of extremely low frequency (ELF) electric fields where as Ampere law is used for magnetic fields. Analysis is carried out using MATLAB software . The assessment of ELF exposure to line operator has been carried out for various scenarios. These assessed values of electric and magnetic field (EMF) exposures are compared with standard allowable limits set by various International Standards. Moreover, the safety of general public living at the edge of right of way (ROW) and 15 m away is evaluated. The objective of the study is to create awareness about the power frequency EMF radiations and its health issues among the power engineers, line operators , general public’s and to electricity utilities, the government to enforce the regulations.
electric-field exposure class as compared with a low exposure class [6]. Quantitative report of long term effect EMF is published in several countries [7-9].Many studies have been reported that children living near transmission line in and around right of way (ROW) had higher cancer and leukaemia incidence than living elsewhere [10]. Many organizations and countries have developed standards and guidelines for permissible limit of EMF exposure levels. These include International Commission on Non-Ionizing Radiation Protection (ICNIRP) [11]. Bonneville Power Administration (BPA) in North America [12]. The Institute of Electronic and Electrical Engineers (IEEE) [13-14] and the American Conference of Governmental Industrial Hygienists (ACGIH) [15]. This paper presents EMF produced by S/C & D/C 1200 KV UHV AC lines for various line operator scenarios. Magnetic field is analysed for full line load current I =3800A. A combination of charge simulation and image method is adopted for evaluation of electric field where as Ampere law is used for magnetic field. Matlab software is used for the analysis. The exposed EMF values are compared with standard limits of exposure published by ICNIRP, IEEE, and ACGIH for live line operator at various scenarios and general public’s living in and around ROW. The remainder of this paper is organized as follows. Systems data and various work scenarios are given in II. The theory of calculation of EMF is depicted in III followed by Emf’s analysis in IV. The comparison of EMF with international standards is listed in V, whereas, the concluding remarks are drawn in VI.
Index Terms—electric field, magnetic field, exposure limits, extremely low frequency.
I. INTRODUCTION Indian power sector is growing at an accelerated pace. To meet the long term power transfer need over a large geographical area, India has adopted 1200 KV Ultra High Voltage (UHV) AC system. The test substation 400/1200 KV has been installed at Bina in Madhya Pradesh, India with 1.1 Km long single circuit (S/C) and 0.8 Km double circuit (D/C) lines[1].The first line is planned to construct from Vardha to Aurangabad having length 382 Km [2]. With increase in system voltage, there is increase in the associated electric and magnetic fields (EMF) and hence, need to examine its impact on design of lines, safety of live line operator’s, behaviour of humans in and around the power lines. Exposure of humans to Extra High Voltage (EHV) /UHV line EMF of extremely low frequency (0-3 KHz ), hereafter we can call power frequency 50Hz, becomes a hot topic of controversial. There are several research publications and reports indicating that prolonged exposure to EMF have health risk [3,4,5]. It is reported that the Soviet switchyard workers were exposed to 50-Hz electric field had suffered health problems such as headaches, fatigue, reduced sexual potency, and a number of other changes among a high © 2013 ACEEE DOI: 01.IJEPE.4.3.18
II. SYSTEM DATA The power lines considered for the analysis are of 200KV, AC 8000 MW, 3800 A. Photographs of S/C horizontal and D/ C vertical tower are shown in figure1. Single and double circuit conductor configuration along with octagonal bundle conductor is depicted in figure 2 and 3 respectively. Distance between two bundle conductor is denoted by ‘S’ and ‘H’ is the conductor height above ground. All the sub-conductors of a bundle are uniformly distributed on a circle of radius ‘R’ as shown in fig.3.The spacing between adjacent subconductors is termed as ‘Bundle Spacing’ and denoted by B. 26